An interesting technology for this disclosure may be, for example, a technology described in Japanese Patent No. 4184394. FIGS. 7, 8, and 9 are cited from Japanese Patent No. 4184394, and respectively correspond to FIGS. 2, 4, and 5 in Japanese Patent No. 4184394. FIGS. 7 to 9 illustrate a first flange portion 1 being a portion of a core included in a coil component, a terminal electrode 2 arranged at the first flange portion 1, and an end portion of a conducting wire 3 that is connected to the terminal electrode 2.
As shown in FIGS. 7 and 9, the conducting wire 3 includes a substantially line-shaped center conductor 4 and an insulating coating layer 5 covering a peripheral surface of the center conductor 4. The terminal electrode 2 includes a base portion 7 arranged on an outer end surface 6 side of the flange portion 1, and a receiving portion 9 extending from the base portion 7 via a bent portion 8. The receiving portion 9 receives an end portion of the conducting wire 3. The terminal electrode 2 further includes a welding portion 11 extending from the receiving portion 9 via a first folded portion 10 and configured to be welded to the center conductor 4 of the conducting wire 3, and a holding portion 13 extending from the receiving portion 9 via a second folded portion 12 and configured to hold and position the conducting wire 3.
For the above-described welding portion 11, FIG. 7 illustrates a state before a welding step is executed, and FIGS. 8 and 9 illustrate a state after the welding step. FIGS. 8 and 9 illustrate a welded ball 14 generated by welding. The welded ball 14 is obtained when a metal molten at welding is cooled and solidified while held in a substantially ball-like shape by surface tension.
The details of the welding step are as follows. In a phase before the welding step, in the terminal electrode 2, the welding portion 11 and the holding portion 13 are open with respect to the receiving portion 9, and do not face the receiving portion 9. FIG. 7 illustrates a state in which the holding portion 13 faces the receiving portion 9; however, the welding portion 11 is open with respect to the receiving portion 9.
The conducting wire 3 is first placed on the receiving portion 9 of the terminal electrode 2. To temporarily fix this state, the holding portion 13 is folded and bent at the second folded portion 12 toward the receiving portion 9 so that the conducting wire 3 is pinched by the receiving portion 9 and the holding portion 13.
Then, as shown in FIG. 7, a portion of the insulating coating layer 5 of the conducting wire 3 on a distal end side with respect to the holding portion 13 is removed. To remove the insulating coating layer 5, for example, irradiation with laser light is applied. It is to be noted that, as well shown in FIG. 9, a portion of the insulating coating layer 5 adjacent to the receiving portion 9 is not removed and is left.
Then, the welding portion 11 is bent at the first folded portion 10 toward the receiving portion 9, and the conducting wire 3 is pinched between the welding portion 11 and the receiving portion 9.
Then, the center conductor 4 of the conducting wire 3 is welded to the welding portion 11. To be more specific, laser welding is applied. The welding portion 11 is irradiated with laser light. Hence, the center conductor 4 of the conducting wire 3 and the welding portion 11 are molten and mixed, and a liquefied molten portion becomes a substantially ball-like shape by surface tension. Consequently, the welded ball 14 is formed as described above.
In the above-described welding step, the molten metal may protrude from the receiving portion 9 of the terminal electrode 2 and reach the bent portion 8 or the base portion 7. Such excessive welding may undesirably cause partial melting or deformation of the bent portion 8 in the terminal electrode 2. Hence, the function of the terminal electrode 2 may not be properly provided.
Owing to this, in the technology described in Japanese Patent No. 4184394, the portion of the insulating coating layer 5 adjacent to the receiving portion 9 is not removed and remains.